Global 3-D ecosystem dynamics and iron cycling model results, 2005 (U.S. JGOFS Synthesis & Modeling Phase project results)

<p>We propose to better quantify the role of marine
ecosystem dynamics on the global ocean carbon cycle, focusing in particular
on air-sea CO2 exchange, net community production, and vertical export.
The research is motivated by two related hypotheses:&nbsp;
<ul>
<li>

multi-nutrient limitation (N, P, Si, Fe) modulates phytoplankton biomass
and primary production, community structure,and biogenic carbon export,&nbsp;</li>

<li>
community structure governs the elemental composition of the exported dissolved
and particulate material, major determinants of subsurface biogeochemical
transport, remineralization, and sequestration.&nbsp;</li>
</ul></p>

<p><br>To this purpose, we will conduct a carefully designed set of numerical
experiments in a global 3-D coupled ecological-biogeochemical-physical
model. The project directly builds upon our recent progress and specific
findings/questions from a global mixed layer ecosystem model that includes
explicit iron limitation and community structure, a full depth 3-D ocean
carbon cycle model, and historical hind-cast simulations (1958-1997) of
ocean physical circulation. Specifically, funding is requested to:&nbsp;
<ul>
<li>
Complete development of a next generation, global 3-D ecological-biogeochemical-physical
model that includes multi-nutrient limitation and explicit geochemical
functional groups (picoplankton, diatoms, Trichodesmium, and coccolithophores).&nbsp;</li>

<li>
Evaluate and iteratively imporve on the simulated uper ocean ecosystem
dynamcs against regional JGOFS data sets, large-scale surface pCO2 and
nutrient fields, and satellite ocean color data using retrospective, historical
simulations for the period 1988-2000.&nbsp;</li>

<li>
Assess the skill of the resulting model in replicating the full depth,
equilibrium distributions of carbon, oxygen and nutreints against the WOCE/JGOFS
global survey data. Test the ecological and biogeochemical impact of dust
deposition, calcification, nitrogen fixation, and silica production by
selective modifications to the base coupled solution.&nbsp;</li>
</ul>
The study directly addresses the overall goal of the U.S. JGOFS Synthesis
and Modeling Project (SMP), to synthesize present knowledge into global
numerical models that can be used for prediction, as well as two of the
major research trajectories highlighted in the SMP program announcement:
\"global and regional studies that link together the biological, physical,
and chemical components of the marine carbon cycle\" and \"synthesis and
modeling efforts that effectively combine field data sets and diagnostic
and prognostic (forward) models\".</p>